Hot metal extrusion apparatus



Oct. 12, 1965 Filed May 11 1962 M. A. SCHEIL 3,210,978

HOT METAL EXTRUSION APPARATUS 2 Sheets-Sheet 1 INVENTOR. MERRILL A. SCHEIL Affonusys Oct. 12, 1965 M. A. SCHEIL 3,210,978

HOT METAL EXTRUSION APPARATUS Filed May 11 1962 2 Sheets-Sheet 2 INVENTOR. MERRILL A. ScHEIL nited States Patent 3,210,978 HOT METAL EXTRUSION APPARATUS Merrill A. Sehell, Milwaukee, Wis assignor to A. 0. Smith Corporation, Milwaukee, Wis a corporation of New York Filed May 11, 1962, Ser. No. 193,974 4 Claims. (CI. 72-39) This invention relates to a hot metal extrusion apparatus and particularly to the fiuid shielding and purging of the extruded metal member.

Wire or rod-like members may be formed by disposing a billet in a die and forcing the billet out through a restricted opening. Metals such as carbon and alloy steels, nickel alloys and some of the other carbon metals can all be extruded into wire-like members to provide any particular cross sectional configuration desired.

In order to facilitate extrusion, it has been found desirable to lubricate the die surfaces normally in contact with the hot metal as well as the surfaces of the extrusion cylinder. In the hot extrusion of metals utilizing certain lubricants, the extruded members tend to form coatings which result from the penetration of the members by the volatile constituents which are carried through the die with the wire being extruded therefrom. This is particularly true in the extrusion of carbon and carbon alloy steel billets. I

The extruded member tends to develop a carbon rich coating adjacent its exterior surface. This undesirable coating is fonned when carbonaceous materials occurring in the extrusion lubricant are gasified by the high extrusion temperatures as the extruded metal leaves the die. At the high temperatures attained as the metal leaves the die, the iron content of the metal is able to absorb quantities of carbon. A carbon-iron solution is formed which initially contains quantities of austenite and cementite. As the carbon concentration increases quantities of ledeburite are formed. As the metal rapidly cools, a two phase solid solution of austenite and cementite forms on the surface of the extruded member, and a quantity of brittle ledcburite fuses to this coating.

The brittle hardness of the high carbon coating, which is primarily due to the presence of ledeburite prevents practical cold drawing of the extruded metal because of wire'fracture and excessive wear on the dies.

The present invention is particularly directed to the provision of a means for preventing carburization or similar reactions with the surface of the extruded metal following its expulsion from the die. In accordance with the present invention, the extruded metal is supported by a guide tube as it is extruded from the die. Means are provided to continuously flush the guide tube with a gaseous medium to continuously shield the extruded metal and to prevent the volatile carbonaceous constituents occurring in the extrusion process from establishing a carbuerizing atmosphere adjacent the extruded metal. Applicant has found air to be a satisfactory and inexpensive gaseous medium for preventing carburization of the extruded metal.

If desired, the guide tube may be heated to maintain the carburizing agents in a volatile state in order to facilitate the flushing and driving off of these agents by the gaseous medium.

The present invention provides a simple and inexpensive apparatus for eliminating or substantially reducing 3,210,978 Patented Oct. 12, 1965 "ice FIG. 2 is a fragmentary enlarged view of a runout assembly including the guide tube shown in FIGURE 1;

FIG. 3 is a top view of a portion of FIG. 2;

FIG. 4 is an enlarged longitudinal section of the guide tube shown in FIGURES 1-3; and

FIG. 5 is a vertical section taken on line 5-5 of FIG. 4.

Referring to the drawings and particularly to FIGURE 1, a hot metal extrusion apparatus is shown including a die assembly 1 having a cylinder 2 defining a die cavity within which a hot metal billet 3 is disposed for extrusion into a relatively small diameter wire 4 of indefinite length and many times the length of the billet 3. A ram 5 forms a part of the extrusion apparatus and is aligned with cylinder 2 and is adapted to be moved into the cylinder 2 and force the hot billet 3 outwardly through a small cylindrical die opening provided in a die nib 6. A runout tube assembly 7 is mounted adjacent the die 6 and supports the hot extruded metal as it is ejected or forced from the die nib 6. A final runout track 8 is provided extending outwardly adjacent the outer end of the runout tube assembly 7 to support the long extruded wire 4.

The illustrated die assembly 1 does not form any particular of this invention and may be .of any suitable construction. The illustrated die assembly 1 is therefore described only in sufficient detail to fully understand the present invention which is particularly directed to the runout tube assembly 7.

Generally, the die assembly 1 includes a support structure 9 for the cylinder 2 and is mounted in trackway 10 on a press bed 11. A pair of upper and lower hydraulic cylinders 12 are fixed to the press bed 11 and connected to structure 9 for limited axial movement with respect to die nib 6.

A die holder 13 is mounted on the press bed 11 with the die nib 6 suitably disposed within a suitable recess immediately adjacent the discharge end of the cylinder 2 opposite from the ram 5. An enlarged passageway in the die holder 13 extends outwardly from the small cylindrical die opening in die nib 6 and directs the extruded metal into the runout tube assembly 7. v

A suitable lubricant 14 covers the internal surface of the cylinder2 and the opening in the die nib 6 to facilitate extrusion of the hot metal billet 3. The lubricant may be one of the common high temperature varieties which usually contain such as aluminum powder or flakes, graphite flakes, and a mineral oil vehicle.

A lubricant such as is described. in the United States patent to A. Clatot et al. 2,757,138 is a suitable lubricating composition for the hot extrusion of metals. A lubricant containing about percent graphite, 10 percent mineral and 20 percent sodium chloride would be satisfactory. Other lubricants which would be expected to act as satisfactory hot extrusion lubricants are: a combination of about 50 percent flake graphite and about 50 percent potassium iodide; a combination of about 33 percent flake graphite, 33 percent sodium chloride, and 33 percent mineral oil; and a lubricant containing a combination of about die nib 6, the working of the metal results in'a further increase in the temperature thereof. Further, portions of the lubricant 14 are volatalined or vaporized and are car-' ried along with the extruded wire 4 into the runout" tubeassembly 7. These substances react undesirably with the 4 surface of the extruded wire 4 to form a hard brittle multiphase carbon coating. The runout tube assembly 7 of the; present invention is constructed to prevent the formationof such coatings.

-In the illustrated embodiment of the invention, the

runout tube assembly 7 includes a guide tube 15 mounted in axial alignment with the enlarged passageway in the die holder 13 and extending axially outwardly therefrom.

A swing tube 16 is releasably secured extending outwardly from the guide tube-15 and is pivotally secured at the outer end to a runout tube 17 which carries the I extruded wire and deposits it upon the runout track 8.

that the oxidizing constituents of air augment the flushing Referring particularly to FIG. 2, the guide tube r15.is

a tubular member mounted within an enlarged passage-- way formed in a die backing and supporting structure including a die backing plate 18, a die plate r19 and a vertiml frame or stool base 20 all of which are carried by' the press bed ll.

The guide tube 15 includes a shear tip 21 secured to i the forwardmost end of the guide tube '15 by a threaded neck 22 which threads into a correspondingly threaded portion of the innermost end of the tube 15. A lock washer 23 is threaded onto the neck 22 immediately adjacent the end of the tube 15 to securely lock the shear tip 21 in place. The diameter of the shear tip 21 is substan-' tially the same as the passageway in the die backing plate 18 and serves to seal the inner surface of the guide tube 15 and to concentrically support the corresponding end of the guide tube 15 within the passageway. The guide tube passageway in stool base 20 is enlarged and defines a locating shoulder 24 with the immediately adjacent face of the die plate 19. Three locating bars 25 are equicircumfercntially spaced about and welded or otherwise secured to the guide tube 15 as by welds 26 and the outer ends are joined by locating rings 27, as most clearly shown in FIG 5. The lomting bars 25 and rings 27 are positioned axially on the guide tube 15 to abut the locating shoulder 24 and locate the end of the shear tip 21 in the plane of the face of the die backing plate 18 immediately adjacent the die holder 13. A tubular coupling member 28 is telescoped over the outer end of the tube 15 and secured thereto as by a circumferential weld (29 at the junction of the tube and the end face of the coupling member. The outer diameter of the coupling member 28 corresponds to the diameter of the passageway in the stool base 20 and the coupling member 28 projects into this passageway to simultaneously seal the corresponding ends of the passageway and coaxi-ally support the co sponding end of the guide tube 15.

The guide tube 15 is provided with a plurality oflongitudinally spaced sets of three equicircumferentially-distributed radial passages 30 which establish fluid communication between the interior of the guide tube 15 and the passageways in the plates 18 and 19 and stool base 20. A gas inlet opening 31 is provided in the stool base-20 and connected by gas conduit 32 to a source of a suitable gas, such as air, under a selected pressure.

As the billet, which may consist of a material such carbon or alloy steel, other carbon metals or nickel alloys, is extruded through the die nib 6, the wire product 4 often reaches a temperature near 2400' F. At this temperature, the iron content of the billet may absorb about 5% of carbon. Therefore, if carbon in a combinable form occurs in guide tube 15, it may penetrate the surface of temperature of about 2065 to 20859 .F., cementite begins to'crystalline'and separate from the solution. Ledebun'te, a eutectic containing about 4.3%; of carbon, begins to for '-m' as 'thewirec'oolsthrough this temperature range. As; the' c ooling;.of. the'wire rather. rapidly progresses, the carbon'isj retained by the wire infthe form of "austenite, cementite' and ledeburite'nndresults in 'a' hard -brittle wire product which is subjectjto transverse crack? ingand-is commercially unsuitable, particularly for cold drawing;

.By contlnuouslyintroducing a gas, such asaininto the Y guide tube d5.under aj selected pressure and adjacent the downstream end of the .extrusiondiefi, the carbonaceous constituents. of the vaporiied portion? ofthe lubricant, whiehpass lntothe' guide tube with the extrudedmetal,

may be rapidly and continuously purgcd'from the guide tube and the zone where the temperature of the wire is at a level which permits the penetration of carbon into the surface thereof;-' While,'for.economic-'reasons, the

gaseous medium generally employed is air,.it is believed and diluting effect of the air being injected into the guide tube. These oxidizing-constituentsfserve to oxidize the carbonaceous elements occurring in guide tube -1-5 thereby preventing their penetration into the "extruded member where they. may combine with the ironfound therein. 'l herefore,-.gaseous-media, other than-air, which include oxidizers would be expected-to render satisfactory noncarburizing results when injected'int'o the guide tube.

The guide tube 15 is of a length which allows all or substantially all of the carburizing constituents present in gurde tube 15 to be rendered'inetfective by being driven ofi and diluted by the air flow within the guide tube. The

extruded wire 4 leaving the guide tube 15'is'general1y reduced in temperature to a point below which carbon rs insoluble in iron and is therefore not subject to further carburrzation. The balance of the runout tube assembly 7 and the runout track 8, therefore, need not be provided with any special air flushing or decarburizing gaseous medium.

Theguide tube 15 is releasably clamped in place by the swing tube 16 which is releasably connected to the outer end of the coupling member 28 of the guide tube 15 by a spring loaded coupling assembly 33. I

Referring particularly to FIGS. 2-4, the coupling member 28 is provided with an outwardly extending reduced tubular portion 34. Atubular coupling 35 is slidably disposed on the reduced tubular portion 34 and abuts a shoulder 36 defined by the reduced portion 34. The opposite end of the tubular coupling 35 is slidably disposed on adjacent end of the swing tube 16. *An axial slot 37 15 provided in the coupling 35 andmates with a radial pin 38 secured to the outer wall of the swing tube 16.

wire 4. The carbon penetrating the wire will initially establish a saturated solution with the iron. As the wire containing a saturated iron-carbon solution cools to a The slot 37 in pin 38 allows limited axial movement of the coupling 35 on swing tube 16 while interconnecting the two members. A coil spring 39 encircles the swing tube 16 between the end of the coupling 35 and a shoulder 40 formedon the tube 16. The. coil 'spring 39 continuously biases-the coupling 35 onto the coupling memberr l8 to releasably interconnect the swing tube 16 to the -'gurde tube 15. Todisconnectthe swing tube 16 from rigidly secured to the outer end-of the swing tube 16 and a similar split clamp portion 43 releasably secured to the adjacent code! the runcut'tube 17: Small pivot pins 44 and 45 are secured to the split clamp portion 43 on opposite sides ofa runout tube 17. The inner ends of the pivot pin: 44 and 45 bear on the adjacent portion of the runout tube 17, as shown in FIG. 2, for swinging movement of the member 41 and the attached swing tube 16 about the vertical axis through pins 44 and 45.

To remove the guide tube 15, the coupling 35 is axially slid onto the swing tube 16 against the bias of spring 39 until the outer end of the coupling 35 clears the coupling member 28. The swing tube 16 is then pivoted about the axis of pins 44 and 45 to the dotted line position of FIG. 3. The guide tube can then be withdrawn from the corresponding passageways.

The runout tube 17 and runout track 8 may be any desired or suitable construction and no further description thereof is deemed necessary to the complete understanding of the invention.

The operation of the present invention is summarized as follows.

The ram 5 is withdrawn from the cylinder 2. The surfaces of the cylinder 2 and die nib 6 subject to contact with a billet are provided with a lubricant 14. A heated metal billet 3 of low carbon steel or any other suitable metal is disposed within the cylinder 2.

Ram 5 is then moved into cylinder 2 to force the billet 3 through the die nib 6 and by extrusion form an elongated wire 4 having a continuous length many times that of the billet 3.

In accordance with the present invention, simultaneously with the initiating of the extrusion process, air is fed into guide tube 15 from line 32. The air enters the guide tube 15 through the many radial passages 30 and moves outwardly through the guide tube 15 and swing tube 16 to maintain a non-carburizing atmosphere about the hot extruded wire 4. The air in the tube 15, which is heated during operation, prevents the formation of appreciable high carbon coatings on the surface of the wire 4.

The present invention thus provides an apparatus of extruding metal members without the formation of undesirable carbide coatings thereupon and is particularly adapted for extrusion of carbon and carbon alloy steel into Wire-like elements which are to be subsequently cold drawn.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In an extrusion apparatus for hot extrusion of a metal through a die opening in a die carried by a support structure,

(a) supporting means disposed contiguous the die opening and having an enlarged passageway projecting outwardly axially of the die opening,

(b) a guide tube slidably disposed within the passagey! (c) means to introduce a shielding medium into said guide tube to continuously flush the guide tube during the extrusion of the metal, and

(d) an extension tube disposed extending axially outwardly from the guide tube removably secured to the guide tube and to the support structure, the extension tube extending axially outwardly from the guide tube and acting to releasably secure the guide tube within the passageway, the extension tube being removable in a direction generally axially outwardly from the guide tube.

2. The extrusion apparatus construction of claim 1 having,

(a) coupling means for removably securing one end of the extension tube to the outer axial end of the guide tube and pivot means secured to the other end of the extension tube for swinging of the extension tube from alignment with the guide tube upon release of said coupling means.

3. In an extrusion apparatus for the hot extrusion of a metal through a die opening in a die,

(a) support means mounted abutting the discharge face of the die and having a passageway aligned with the die opening,

(b) a guide tube of a smaller diameter than said pas sageway and concentrically mounted therein and having a plurality of longitudinally spaced radial apertures providing communication between the guide tube and the passageway,

(c) a locating tip secured to the end of the guide tube adjacent the die opening to seal the passageway externally of the guide tube,

((1) locating means secured to the guide tube and cooperating with the support means to axially locate the guide tube,

(e) an outer locating member secured to the outer end of the guide tube and partially telescoped within the outer end of the passageway to close the passageway and radially locate the guide tube,

(f) a swing tube member disposed to project axially outwardly from the outer end of the guide tube,

(g) a coupling member slidably disposed over the adjacent ends of the swing tube and outer locating member to support the corresponding end of the swing tube,

(h) means resiliently holding the coupling means in the swing tube and outer locating member and permitting disengagement thereof from one of the associated members,

(i) a pivot mounting secured to the outer end of the swing tube permitting swinging of the swing tube from alignment with the guide tube upon release of the coupling means for removing of the guide tube, and

(j) means to introduce a gaseous medium into the passageways containing said guide tube to continuously force the gaseous medium into the guide tube and into shielding relation with the extruded metal and axially outwardly therefrom through said swing tube, the gaseous medium including an oxidizing agent.

4. In an extrusion apparatus for the hot extrusion of a metal through a die opening in a die,

(a) a die backing plate mounted adjacent the discharge face of the die and having a passageway aligned with the die opening,

(b) a die plate mounted abutting the backing plate and having a similar diameter passageway aligned with the passageway in the backing plate.

(c) a mounting plate mounted abutting the die plate and having a greater diameter passageway aligned with the passageway in the die plate,

(d) a guide tube of a smaller diameter than each of said passageways concentrically disposed within said passageways and having a plurality of longitudinally spaced radial apertures providing communication between the guide tube and the passageways,

(e) a locating tip secured to the end of the guide tube within the die backing plate to seal the passageway externally of the guide tube,

(f) a plurality of locating means secured to the guide tube in accordance with the location of the junction of the die plate and the mounting plate and abutting the die plate to axially locate the guide tube,

(g) a locating member secured to the outer end of the guide tube and partially telescoped within the outer end of the mounting plate to seal the passageway therein and to radially locate the guide tube,

(h) a swing tube disposed to project axially outwardly from the outer end of the guide tube,

(i) a sleeve coupling slidably disposed over the adjacent ends of the swing tube and the locating member to support the corresponding end of the swing tube,

(j) a slot and pin connection between the sleeve coupling and the swing tube to allow retraction of the sleeve coupling from the locating member,

(k) an abutment centrally of the swing tube,

(1) a coil spring encircling the swing tube between the sleeve coupling and said shoulder,

(in) a pivot mounting secured to the outer end of the 7 8 swing tube permitting swinging of the swing tube from 2,975,893 3/61 Johnson 207-2 alignment with the guide tube upon release of the sleeve 3,014,583 12/61 Huffman et al 207-2 coupling for removing of the guide tube, and 3,040,884 6/62 Haendeler 207--l6 (n) means to introduce air into the passageways con- 3,120,305 2/64 Linnerz 20710 taining said guide tube to continuously force the air into 5 the guide tube and axially outwardly therefrom through FOREIGN PATENTS said swing tube. 1,116,180 11/61 Germany.

References Cited by the Examiner gig; UNITED STATES PATENTS 10 2,097,502 11/37 Southgate 207 10.11 OTHER REFERENCES 2,359,453 10/44 Waldron 207 1.2 Metals Handbook, 1948 ed., published by: The Ameri- 2,639,810 5/53 Doan 207-10 can Society for Metals, Cleveland (page 5, definition of 2,671,558 3/54 Remington et a1. 2071.2 decarburization relied upon). 2,698,267 12/54 Halversen 207-10.11 15 2 65 502 12 53 Anschfir 2Q7 16 CHARLES W. LANHAM, Przmary Examiner. 2,883,049 4/59 Arenz 20716 WILLIAM w. DYER, JR., MICHAEL v. BRINDISI,

2 954 121 9/60 Benson 2071.2 Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,210 ,978 October 12 1965 Merrill A. Scheil It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, lines 57 and 58, strike out "disposed extending axially outwardly from the guide tube".

Signed and sealed this 11th day of October 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Atlesting Offieer Commissioner of Patents 

1. IN AN EXTRUSION APPARATUS FOR HOT EXTRUSION OF A METAL THROUGH A DIE OPENING IN A DIE CARRIED BY A SUPPORT STRUCTURE, (A) SUPPORTING MEANS DISPOSED CONTIGUOUS THE DIE OPENING AND HAVING AN ENLARGED PASSAGEWAY PROJECTING OUTWARDLY AXIALLY OF THE DIE OPENING, (B) A GUIDE TUBE SLIDABLY DISPOSED WITHIN THE PASSAGEWAY, (C) MEANS TO INTRODUCE A SHIELDING MEDIUM INTO SAID GUIDE TUBE TO CONTINUOUSLY FLUSH THE GUIDE TUBE DURING THE EXTRUSION OF THE METAL, AND (D) AN EXTENSION TUBE DISPOSED EXTENDING AXIALLY OUTWARDLY FROM THE GUIDE TUBE REMOVABLY SECURED TO THE GUIDE TUBE AND TO THE SUPPORT STRUCTURE, THE EXTENSION TUBE EXTENDING AXIALLY OUTWARDLY FROM THE GUIDE TUBE AND ACTING TO RELEASABLY SECURE THE GUIDE TUBE WITHIN THE PASSAGEWAY, THE EXTENSION TUBE BEING REMOVABLE IN A DIRECTION GENERALLY AXIALLY OUTWARDLY FROM THE GUIDE TUBE. 